1. Field of the Invention
The invention relates to measuring and testing, especially to the detection of fluid temperature and related data. An air temperature probe is disclosed for use in making in-flight temperature measurements on aircraft operating in an airstream.
2. Description of the Prior Art
Temperature probes suitable for use on aircraft are required to make fast, accurate, continuous temperature measurement of the outside air in the airstream surrounding the aircraft. The measurement is used for a variety of purposes, including the adjustment of air/fuel ratios. Air temperature is well recognized as an important factor to be known when operating an aircraft.
The accuracy and time constant are two factors by which temperature sensors are judged. Accuracy is often impaired due to dynamic airstream heating and measurement falsification by heated housings. In the past, it has been necessary to create heated temperature probe housings in order to prevent icing, and the heated air must then be deflected in some manner to prevent a false reading, or alternatively, the temperature sensing element must compensate for the expected influence of the heating element. In either case, inaccuracies are introduced into the temperature reading.
The temperature sensing element on an aircraft is always mounted in a housing for the purpose of protecting the element from damage, for example from the impact of rain, ice, hail, dust or air velocity. Often the air flow inside the housing is deflected at 90.degree. from the direction of entry in order to separate particles by inertial force. Deflection of air flow can result in slower response time of the sensor and inaccurate readings. Deflection of the air stream may result in turbulence, disrupting the fast time response of the instrument relative to the speed of the aircraft.
The invention is an air temperature probe that offers ice free performance without heating, and senses temperatures with superior accuracy and time constant.